The general Bandpass-
problem is NP-hard and can be approximated by a reduction into the
-set packing problem, with a worst case performance ratio of
= 2, a maximum weight matching gives a 2-approximation to the problem. The Bandpass-2 problem, or simply the Bandpass problem, can be viewed as a variation of the maximum traveling salesman problem, in which the edge weights are dynamic rather than given at the front. We present in this paper a
-approximation algorithm for the Bandpass problem, which is the first improvement over the simple maximum weight matching based 2-approximation algorithm.